616 AMMIACEAE 



Leaves bi- or tri-pinnate ; segments filiform; bractlets not exceeding the pedicels; seeds 

 subterete. 1. D. tenuifolium. 



Leaves pinnate; segments narrowly linear; bractlets longer than the pedicels; seeds, 

 somewhat depressed. 2. D. linearis. 



1. D. tenuifolium (Nutt.) Rydb. Leaves glaucous; peduncles 1-2.5 dm. 

 high, glabrous; flowers cream- white or ochroleucous; fruit 3-4 mm. long, puberu- 

 lent or nearly glabrous; oil-tubes 2 or 3 in the intervals. Musenium tenuifolium 

 Nutt. Dry hills and plains: S.D. Neb. Wyo. Plain Submont. My-Jl. 



2. D. linearis Rydb. Stems glabrous, weak, 1-2 dm. high; leaf-segments 

 entire, 1-3 cm. long; branches of the umbels 2-4 mm. long; fruit nearly sessile, 

 oblong, 3-4 mm. long, strongly ribbed; oil- tubes 2 or 3 in the intervals. Aletes 

 tenuifolia Coult. & Rose. Mountains: Utah. Submont. Jl. 



19. ALETES Coult. & Rose. 



Low cespitose, acaulescent perennials. Leaves pinnate, with broad, sharply 

 toothed or cleft, distant leaflets. Flowers yellow, in small umbels. Calyx-teeth 

 prominent. Stylopodium wanting. Fruit flattened laterally, oblong, glabrous. 

 Ribs equal and prominent, but not winged. Oil-tubes large and solitary in 

 each broad interval, 2 on the commissural side, and a small one in each rib. 

 Seeds sulcate beneath each oil-tube; face slightly concave or plane. 



Peduncles longer than the leaves; branches of the umbels short. 



Leaflets rounded-obovate in outline; their teeth ovate; fruit 5-6 mm. long. 



1. A. obovata. 



Leaflets rhombic-cuneate in outline, incised-toothed, with lanceolate-acuminate teeth; 



fruit 4-5 mm. long. 2. A. acaulis. 



Peduncles shorter than the leaves; branches of the umbels nearly as long as the peduncles. 



3. A. humilis. 



1. A. obovata Rydb. Peduncles 1-3 dm. high; leaves 1-2 dm. long, pin- 

 nate with 4-5 pairs of leaflets; these broadly obovate, 1-2 cm, long, more or less 

 cleft and toothed, with short ovate teeth, strongly veined beneath; branches of 

 the umbel 2-2.5 cm. long in fruit; fruit 5-6 mm. long and 1.5 mm. in diameter; 

 ribs rather thick. Mountains: Colo. Submont. Ap-Je. 



2. A. acaulis (Torr.) Coult. & Rose. Peduncles 1-3 cm. high; leaflets 

 rhombic or rhombic-ovate, cut with lanceolate-acuminate teeth; branches of the 

 umbels 1-2 cm. long; fruit 4-5 mm. long, almost sessile. High mountains: 

 Colo. N.M. Submont. Mont. My-Au. 



3. A. humilis Coult. & Rose. Peduncles 2-5 cm. long; leaflets usually 5, 

 entire or few-toothed, elliptic to obovate; branches of umbels spreading, 2.5-3 

 cm. long; fruit ovate, 3 mm. long. Mountains: Colo. Mont. Je. 



20. OREOXIS Raf. 



Acaulescent cespitose perennials. Leaves pinnate, the leaflets cut into 

 lanceolate, acute divisions. Flowers yellow or yellowish, in small umbels. 

 Involucres none; involucels of narrow bractlets. Calyx-teeth prominent. 

 Fruit globose to oblong, slightly flattened laterally. Ribs prominent, thick 

 and corky. Stylopodium wanting. Oil-tubes 1-3, in the very narrow inter- 

 vals, 2 on the commissural side. Seeds slightly depressed, somewhat sulcate 

 under the oil-tubes; face plane or nearly so. 



Oil-tubes more than one in each interval; plant less than 1 dm. high, glabrous. 

 Bractlets linear, entire. 1. O. hurmhs. 



Bractlets obovate or oblanceolate, toothed. 2. O. Baken. 



Oil-tubes solitary in each interval. 



Plant less than 1 dm. high, more or less puberulent, at least the upper part of the 



peduncle; leaflets cleft into 1-7 linear divisions, which are 4-5 mm. long; fruit 



4-5 mm. long. 3. O. alpina. 



Plant 1-2 dm. high, glabrous; leaflets ovate or lanceolate, few-toothed, 5-15 mm. 



long; fruit oblong, 6-7 mm. long. 4. O. MacDougah. 



1. O. humilis Raf. Leaves 4-7 cm. long; leaflets cut into 3-7 linear-lance- 

 olate divisions; peduncles 2-7 cm. long, glabrous or slightly puberulent below 

 the umbel; flowers bright yellow; fruit 3^ mm. long; oil-tubes 2 or 3 (rarely 1) 

 in the intervals. High mountain peaks: Colo. Subalp. Alp. Je-Au. 



